Sigh. I will expand.

Moving your saddle around can have slight effects on handling inasmuch you are altering your fit and balance, which have some consequences for bike handling. If moving it back is a better fit and improves your balance, you may see some benefit to your ability to handle the bike. On the other hand, if it worsens your fit, you may see the opposite. There is certainly no easily predictable, large effect of saddle fore/aft positioning on handling.

On the whole, these effects will be very small, and it's hard to imagine that they are going to be noticed by most people. If your bike fit is poor enough to have a negative effect on handling, the remedy is going to require more than simply sliding the saddle around. Significant handling problems related to fit (a diagnosis that might be hard to make!) are most likely when the frame simply doesn't fit, especially if it is too large.

Hope that helps.